Qualitative assessment of compost products of Tehran and Khomein facilities, Iran

The objective of this research was to study the quality and compare the compost product of Khomein and Tehran compost facilities. For investigation the chemical quality of these materials, some indices such as organic materials, carbon, nitrogen, phosphorus, potash and heavy metals which consisting of lead, cadmium, mercury and chromium were measured. Microbial quality of samples was defined by assessing the amounts of coliforms, salmonella and parasites ova. The average amounts of considered parameters of Khomein and Tehran composts were: organic materials (٣٧.٧٧, ٢٩.٨٠%), carbon (٢٢.١٤, ١٨.١٢%), nitrogen (٢.٠٨, ١.٦%), lead (٢٢٩.٦, ٥٩.٤٤ ppm), and chromium (٧٠.٢, ١٩.٧٥ ppm), respectively. The microbial quality of these compost samples were in agreement with compost class B. This study showed that organic materials in Tehran’s samples were better than Khomein’s samples, but these parameters were lower than compost class ٢. The carbon, nitrogen and potash percents in these samples were desirable but, phosphorus was not in sufficient. The heavy metals concentration especially lead and chromium in Tehran’s samples were higher than Khomein’s samples, but these samples were usually in agreement with guidelines of compost. Due to the defined microbial qualities, these composts could be used as amendment agents for poor soils